I once had the same issue on my 2005 e90 320d sometime last year. The mistake i did was to buy a new clutch kit and a second had DMF. The car drove of for a month or so but the problem came back. So i had to buy a new clutch kit and a new flywheel, R3K and R3,5 from Goldwagen. I took those to Tunetech and they charged me R2K for labour. Problem solved. The car drove like never before and felt smooth when shifting.
My advice would be to get quotes on the clutsh kit and DMF from at least 3 reputable spares dealership. Then take those to BMW or Tunetech if you are JHB. Total cost will be around R12K or less. Because what happens is when you send in your car for repairs, the shops have to order the spares from the manufactures and add a markup (sorry an abnormal mark-up). Dealership dont make these spares on their own.
All the best!!